require 'date'
require 'sys/admin'

begin
  require 'win32/file'
rescue LoadError
  # Do nothing, not required, just nicer.
end

class File::Find
  # The version of the file-find library
  VERSION = '0.3.9'

  # :stopdoc:
  VALID_OPTIONS = %w[
    atime
    ctime
    follow
    ftype
    inum
    group
    links
    maxdepth
    mindepth
    mount
    mtime
    name
    pattern
    path
    perm
    prune
    size
    user
  ]
  # :startdoc:

  # The starting path(s) for the search. The default is the current directory.
  # This can be a single path or an array of paths.
  #
  attr_accessor :path

  # The list of options passed to the constructor and/or used by the
  # File::Find#find method.
  #
  attr_accessor :options

  # Limits searches by file access time, where the value you supply is the
  # number of days back from the time that the File::Find#find method was
  # called.
  #
  attr_accessor :atime

  # Limits searches by file change time, where the value you supply is the
  # number of days back from the time that the File::Find#find method was
  # called.
  #
  attr_accessor :ctime

  # Limits searches to files that belong to a specific group, where the
  # group can be either a group name or ID.
  #
  attr_accessor :group

  # An array of two element arrays for storing FileTest methods and their
  # boolean value.
  #
  attr_accessor :filetest

  # Controls the behavior of how symlinks are followed. If set to true (the
  # default), then follows the file pointed to. If false, it considers the
  # symlink itself.
  #
  attr_accessor :follow

  # Limits searches to specific types of files. The possible values here are
  # those returned by the File.ftype method.
  #
  attr_accessor :ftype

  # Limits search to a file with a specific inode number.
  #
  attr_accessor :inum

  # Limits search to files with the specified number of links.
  #
  attr_accessor :links

  # Limits search to a maximum depth into the tree relative to the starting
  # search directory.
  #
  attr_accessor :maxdepth

  # Limits searches to a minimum depth into the tree relative to the starting
  # search directory.
  #
  attr_accessor :mindepth

  # Limits searches to the same filesystem as the specified directory. For
  # Windows users, this refers to the volume.
  #
  attr_reader :mount

  # Limits searches by file modification time, where the value you supply is
  # the number of days back from the time that the File::Find#find method was
  # called.
  #
  attr_accessor :mtime

  # The name pattern used to limit file searches. The patterns that are legal
  # for Dir.glob are legal here. The default is '*', i.e. everything.
  #
  attr_accessor :name

  # Limits searches to files which have permissions that match the octal
  # value that you provide. For purposes of this comparison, only the user,
  # group, and world settings are used.
  #
  # You may optionally use symbolic permissions, e.g. "g+rw", "u=rwx", etc.
  #
  # MS Windows only recognizes two modes, 0644 and 0444.
  #
  attr_accessor :perm

  # Skips files or directories that match the string provided as an argument.
  #
  attr_accessor :prune

  # If the value passed is an integer, this option limits searches to files
  # that match the size, in bytes, exactly. If a string is passed, you can
  # use the standard comparable operators to match files, e.g. ">= 200" would
  # limit searches to files greater than or equal to 200 bytes.
  #
  attr_accessor :size

  # Limits searches to files that belong to a specific user, where the user
  # can be either a user name or an ID.
  #
  attr_accessor :user

  # The file that matched previously in the current search.
  #
  attr_reader :previous

  alias pattern name
  alias pattern= name=

  # Creates and returns a new File::Find object. The options set for this
  # object serve as the rules for determining what files the File::Find#find
  # method will search for.
  #
  # In addition to the standard list of valid options, you may also use
  # FileTest methods as options, setting their value to true or false.
  #
  # Example:
  #
  #    rule = File::Find.new(
  #       :name      => "*.rb",
  #       :follow    => false,
  #       :path      => ['/usr/local/lib', '/opt/local/lib'],
  #       :readable? => true
  #    )
  #
  def initialize(options = {})
    @options = options

    @atime  = nil
    @ctime  = nil
    @ftype  = nil
    @group  = nil
    @follow = true
    @inum   = nil
    @links  = nil
    @mount  = nil
    @mtime  = nil
    @perm   = nil
    @prune  = nil
    @size   = nil
    @user   = nil

    @previous = nil
    @maxdepth = nil
    @mindepth = nil
    @filetest = []

    validate_and_set_options(options) unless options.empty?

    @filesystem = File.stat(@mount).dev if @mount

    @path ||= Dir.pwd
    @name ||= '*'
  end

  # Executes the find based on the rules you set for the File::Find object.
  # In block form, yields each file in turn that matches the specified rules.
  # In non-block form it will return an array of matches instead.
  #
  # Example:
  #
  #   rule = File::Find.new(
  #      :name    => "*.rb",
  #      :follow  => false,
  #      :path    => ['/usr/local/lib', '/opt/local/lib']
  #   )
  #
  #   rule.find{ |f|
  #      puts f
  #   }
  #
  def find
    results = [] unless block_given?
    paths   = @path.is_a?(String) ? [@path] : @path # Ruby 1.9.x compatibility

    if @prune
      prune_regex = Regexp.new(@prune)
    else
      prune_regex = nil
    end

    paths.each{ |path|
      begin
        Dir.foreach(path){ |file|
          next if file == '.'
          next if file == '..'

          if prune_regex
            next if prune_regex.match(file)
          end

          file = File.join(path, file)

          stat_method = @follow ? :stat : :lstat
          # Skip files we cannot access, stale links, etc.
          begin
            stat_info = File.send(stat_method, file)
          rescue Errno::ENOENT, Errno::EACCES
            next
          rescue Errno::ELOOP
            stat_method = :lstat # Handle recursive symlinks
            retry if stat_method.to_s != 'lstat'
          end

          # We need to escape any brackets in the directory name.
          glob = File.join(File.dirname(file).gsub(/([\[\]])/,'\\\\\1'), @name)

          # Dir[] doesn't like backslashes
          if File::ALT_SEPARATOR
            file.tr!(File::ALT_SEPARATOR, File::SEPARATOR)
            glob.tr!(File::ALT_SEPARATOR, File::SEPARATOR)
          end

          if @mount
            next unless stat_info.dev == @filesystem
          end

          if @links
            next unless stat_info.nlink == @links
          end

          if @maxdepth || @mindepth
            file_depth = file.split(File::SEPARATOR).length
            path_depth = @path.split(File::SEPARATOR).length
            depth = file_depth - path_depth

            if @maxdepth && (depth > @maxdepth)
              if File.directory?(file)
                unless paths.include?(file) && depth > @maxdepth
                  paths << file
                end
              end

              next
            end

            if @mindepth && (depth < @mindepth)
              if File.directory?(file)
                unless paths.include?(file) && depth < @mindepth
                  paths << file
                end
              end

              next
            end
          end

          # Add directories back onto the list of paths to search unless
          # they've already been added
          #
          if stat_info.directory?
            paths << file unless paths.include?(file)
          end

          next unless Dir[glob].include?(file)

          unless @filetest.empty?
            file_test = true

            @filetest.each{ |array|
              meth = array[0]
              bool = array[1]

              unless File.send(meth, file) == bool
                file_test = false
                break
              end
            }

            next unless file_test
          end

          if @atime || @ctime || @mtime
            date1 = Date.parse(Time.now.to_s)

            if @atime
              date2 = Date.parse(stat_info.atime.to_s)
              next unless (date1 - date2).numerator == @atime
            end

            if @ctime
              date2 = Date.parse(stat_info.ctime.to_s)
              next unless (date1 - date2).numerator == @ctime
            end

            if @mtime
              date2 = Date.parse(stat_info.mtime.to_s)
              next unless (date1 - date2).numerator == @mtime
            end
          end

          if @ftype
            next unless File.ftype(file) == @ftype
          end

          if @group
            if @group.is_a?(String)
              if File::ALT_SEPARATOR
                begin
                  next unless Sys::Admin.get_group(stat_info.gid, :LocalAccount => true).name == @group
                rescue Sys::Admin::Error
                  next
                end
              else
                begin
                  next unless Sys::Admin.get_group(stat_info.gid).name == @group
                rescue Sys::Admin::Error
                  next
                end
              end
            else
              next unless stat_info.gid == @group
            end
          end

          if @inum
            next unless stat_info.ino == @inum
          end

          # Note that only 0644 and 0444 are supported on MS Windows.
          if @perm
            if @perm.is_a?(String)
              octal_perm = sym2oct(@perm)
              next unless stat_info.mode & octal_perm == octal_perm
            else
              next unless sprintf("%o", stat_info.mode & 07777) == sprintf("%o", @perm)
            end
          end

          # Allow plain numbers, or strings for comparison operators.
          if @size
            if @size.is_a?(String)
              regex = /^([><=]+)\s*?(\d+)$/
              match = regex.match(@size)

              if match.nil? || match.captures.include?(nil)
                raise ArgumentError, "invalid size string: '#{@size}'"
              end

              operator = match.captures.first.strip
              number   = match.captures.last.strip.to_i

              next unless stat_info.size.send(operator, number)
            else
              next unless stat_info.size == @size
            end
          end

          if @user
            if @user.is_a?(String)
              if File::ALT_SEPARATOR
                begin
                  next unless Sys::Admin.get_user(stat_info.uid, :LocalAccount => true).name == @user
                rescue Sys::Admin::Error
                  next
                end
              else
                begin
                  next unless Sys::Admin.get_user(stat_info.uid).name == @user
                rescue Sys::Admin::Error
                  next
                end
              end
            else
              next unless stat_info.uid == @user
            end
          end

          if block_given?
            yield file
          else
            results << file
          end

          @previous = file unless @previous == file
        }
      rescue Errno::EACCES
        next # Skip inaccessible directories
      end
    }

    block_given? ? nil : results
  end

  # Limits searches to the same file system as the specified +mount_point+.
  #
  def mount=(mount_point)
    @mount = mount_point
    @filesystem = File.stat(mount_point).dev
  end

  private

  # This validates that the keys are valid. If they are, it sets the value
  # of that key's corresponding method to the given value. If a key ends
  # with a '?', it's validated as a File method.
  #
  def validate_and_set_options(options)
    options.each do |key, value|
      key = key.to_s.downcase

      if key[-1].chr == '?'
        sym = key.to_sym

        unless File.respond_to?(sym)
          raise ArgumentError, "invalid option '#{key}'"
        end

        @filetest << [sym, value]
      else
        unless VALID_OPTIONS.include?(key)
          raise ArgumentError, "invalid option '#{key}'"
        end

        send("#{key}=", value)
      end
    end
  end

  # Converts a symoblic permissions mode into its octal equivalent.
  #--
  # Taken almost entirely from ruby-talk: 96956 (Hal Fulton).
  #
  def sym2oct(str)
    left  = {'u' => 0700, 'g' => 0070, 'o' => 0007, 'a' => 0777}
    right = {'r' => 0444, 'w' => 0222, 'x' => 0111}
    regex = /([ugoa]+)([+-=])([rwx]+)/

    cmds = str.split(',')

    perm = 0

    cmds.each do |cmd|
      match = cmd.match(regex)
      raise "Invalid symbolic permissions: '#{str}'" if match.nil?

      who, what, how = match.to_a[1..-1]

      who  = who.split(//).inject(0){ |num,b| num |= left[b]; num }
      how  = how.split(//).inject(0){ |num,b| num |= right[b]; num }
      mask = who & how

      case what
        when '+'
          perm = perm | mask
        when '-'
          perm = perm & ~mask
        when '='
          perm = mask
      end
    end

    perm
  end
end
